Sprocket



June 2, 1931. T. BJMUNROE SPROCKET Filed-June 21 1925 2 Sheets-Sheet 1June 2, 1931. "r. a. MU'NROE 8,3

SPROCKET Filed June 21 1925 2 Sheets-Sheet 2 '20 tofore employedsprocket;

Patented June 2,1931

. eases UNITED STATES PATENT F-loaf I I TREADWAY B. 'MUNROE, OF CHICAGO,ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO THE CELO'IEX COMPANY, or CHICAGO, ILLINOIS, A CORPORATION or DELAWAREsrnocxnr Application filed June 21, 1928. Serial No. 117,644. 7

This invention relates to a sprocket, and more especially to that typeadapted to be driven rather than to drive, and has for its object toprovide a-construction more ef ficient in use than those heretoforeproposed.

With this and other objects in view, the in vention consists in thenovel details of construction and combinations of parts as will be morefully hereinafter disclosed and par la ticularly pointed out in theclaims.

Referring to the accompanyingdrawings, forming a part of thisspecification, in which like numerals designate like partsin alltheviews I 1 V Fig. 1 illustratesv a device adapted to be driven throughthe use of a type of sprocket heretofore employed;

Fig. 2 is a view similar to Fig. 1 showing the substitution of thisinvention for the herewith the result that the material was dragged overthese. non-rotating rollers,the friction therefrom working against theefiicientdelivery of the material from the dryer. Guide blocks or shoeshad to be provided which were secured to the framing of the apparatusand which were adapted. to overlie the driving chain at frequentintervals to keep said chain down in mesh with the sprocket teeth.However, this was found objectionable in that said shoes and the chainbecame worn from their sliding contact causing expensive re-.placements. Considerable experimentation followed with different typesof sprockets,

etc, to overcome this deficiency, thus develop} come the aboveobjections to be 'of'value otherwise.

Referring to the "drawings, there is disclosed in .Fig. 1 one of a pairof side frame members, numbered 1, in which is suitably journaledtheends of the 'tubularrollers 2 adapted to conveythe material 3 to bedried. On one end of each of the rollers is securely fixed the sprocket4; the teeth of" which are adapted to be engaged by the driving chain 5which receives its motion froma shaft 6 whichin turn derives its powerfrom a source not shown through a main driving chain 7 and'sprocket 8,all as will be clearly understood from said figure and with reference tomy aforementioned patent. 9 designates any suitable type of adjustmentby which the chain 5 may be kept substantially taut. However, it will beobserved that the pitch of the teeth of the sprocket 4 is the same asthe link distance or pitchvof the chain 5', and further, that each toothhas a face 10 which is substantially radially formed. The resultjvofthis construction is that the pins but has proved Fig. '3 is an enlargeddetail view similar to Fig. 2 and adapted to illustrate the operation ofasprocket made in accordance with this invention; v

Fig. 4 is a greatly enlarged view .of the improved sprocket; and v Fig.5 is a sectional view taken on the line 55 of Fig. 4 and looking in thedirection of the arrows. I

In order that this invention may be the more clearly understood it issaid that in my U. S. Letters Patent #1,501,966,-dated July 22, 1924:,there is disclosed a drying apparatus in which there is provided a;great plurality of rollers adapted to support and move the materialpassing through the dryer. On

one end of each of these rollers there is secured a sprocket which isadapted to be engagedby a driving chain so that said chain 4?. willrotate, at uniform speed, the rollers car rying the material. However,greater difficulty was experienced in the use of this particular type ofsprocket in that the driving chain rode up and over the end of the teethof the sprocket without revolving the rollers,

and off said facelO because the weight of said chain is insufficient toinsure the same meshing with each sprocket 4:. The result 6oing thesprocket forming .the subject matter of this application which has notonly over-;

or pintles of the chain 5 will ride upwardly of this is that the chain 5will pass over a great number of the sprockets 5 without engaging thesame, thus leaving the rollers associated with the non-rotatingsprockets immovable.

In Figs. 2 and 3 substantially the same numerals have been used todesignate similar and like parts, but in these figures it willbeo'bserved that the improved sprocket 15 has been employed, and thatthe face '16 of each tooth. corresponding totheface 10 of the teeth ofthe sprocket a illustrated inFiIq. 1, is not radially disposed. but isoutwardly and rearwardly inclined thus producing a hook-shaped tooth."Assuming the generally adopted definition ofjthe pitch 'of the teeth ofany sprocket as being the distance on the pitch line from the center ofone tooth-to the center of the next adjacent tooth, and

further assuming that all the teeth are syinmetrically formed. withequal dimensions, then it will be obvious that the'distance from anypoint. on the pitch line associated with a tooth to a symmetrical pointon said pitch. line associated with the next adjacent tooth will beequal to the pitch distance ofsaid sprocket. Therefore. with particularrefer- 7 once to Fig. 4. it will he observed'that the dot anddash line17 is representative. of the pitch distance oft-he sprocket teeth inas-vmuch as said line is equal in length .to the distance between the.twosinall circle-s-rep resenting; the centers of curvature,ofithepockets of two adjacent symmetrical teeth. In the following,discussion,therefore. the line '17 is referred to as the pitch of theteeth. of the sprocket 15, and from. said Fig.

4.- it will be observed thatsaid pitch is-less;

than the link distance or the pitch 18 of the chain. It will stillfurther be observed that the end of eachtooth 19 of this-sprocket hasbeen angularly cut offto provide anarcu atel-y chamfered surface 20'sothat there will be provided a space 21 betweensaidchamfer 20 and theouter circumference otthe pintle 22 of the chain 5 when Stlll0l1f1l-ILPHSSQ$ over.

said so r0 cket.

- In Fig. 4:, there isclearlyshownthe-formal? tion of eachtooth 19 ofthe sprocket a ad from. said figure-it, will'be seen thatgthe-siu'face16 of each tooth is flat, as is alsothe oppm site face 23, but that thelatter'face is longrer than; the former. and disposed at-suchawule angleto the radius ofthe sprocket as will give to-the tooth maximum bracingstrength against the thrust of the chain 5; That is to say, said surfacel6 constitutes the work 'ing surface of the tooth and lies ini'a plane24: tangent toa circle 25 as at the point 26" which is to oneside ofthe'center-27 of the sprocket. Statedin stillother language, a

' radial'line 28 drawn: from the centerf27: of

the sprocket through an apexz29 of any tooth will intersect the plane24' passing through 1 the face 16 of that tooth. Thus it will beparticular pintle 32, moving in the directionof the arrow, will havebecome seated in thepocket therefor,- with the result that said pintlewill'bear against the surface 16 of the tooth 3'3 and causethe same torotate the sprocket the directionjindicated. The chain/5 being undercontinual motion, will move the sprocketand cause the next fol-- lowingtooth 34 to move upwardly and around toward the left as seen in Fig. 4.But due to its pitch distance from its preceding tooth 33, and also dueto its novel and peculshape, the apex OfftOOth 34 will easily pass intothe space between the pintles 32 and 36 with the result that, assaidchain continues to move to the left, the pintle 32 willcause therotation of the sprocket tocontin-ue until said pintle has passed theposition illustrated in Fig. lbefore it will have a tendency to ride up,the surface 160f the tooth 33.

This will be perfectly obvious, but may be statedas caused by the factthat in the position-illustrated in Fig. 4 the surface 16 of the tooth33 is in a. substantially vertical plane, and therefore the pintle 32will not move over said surface .until the surface has assumed. anangular position further to the left as seen in said figure. surface" 16of the tooth 33 haslreached that particular. angularfposition at whichthe pintle 32 will tendtomove upwardly there overathe next following.tooth 34 of the sprocket will have moved upwardly and totheleft solthatthe chamfered surface 20 0f. the end of said tooth will lie above thehorizontal center of thefollowing pintle 36- of the chain 5. Continuedmovement to theleft "of the chain 5, will cause the circumference 22 ofthe pintle; 3.6 to, contact with the chamferedsurface 20 of said tooth3avwhen.

thepreceding pintle-32 begins to leave its pocket 30; with the resultthat said. chamtherefrom,thus. insuring the seating-of said But whenthe:

pintle 36 in the pocket behind said tooth 343.

and causing the continuedrotatiori of the. sprocket 15 bypressingagainst said tooth Thusit'wilt be seen that each linkof the chain isforced downwardly into engagement with t-he spro'ck et 15,01 inotherwords, pre-- vented from jumping v-oif of said sprocket.

practically negligible in so far as the move ment of the material to bedelivered in the apparatus is concerned.

In Fig. is shown a' sectionalview of the sprocket 15 and in which isparticularly illustrated the hub portion l0 extending to either side ofthe plane of the-teeth 19 to form a relatively wide bearing surface 41with the ment a pintle such as 32 of the chain due to outercircumference of the hub of the tubular.

drying rolls 2; The sprocket 15 is adapted to be securedt-othe rolls byany suit-able means, such as the usual set screws not shown butoperating in the threaded bores 42- with which the hub 40 of thesprocket is provided, said bores being on opposite sides of the plane ofthe teeth 19. I

From the foregoing, it will therefore be seen that there is provided asprocket adapted to be driven by a tangential chain which is providedwith means to retain said chain and sprocket in engagement. In otherwords, this particular sprocket is not adapted at all for use withchains which wrap around said sprocket to any appreciable extent,because the pitch of the teeth of the sprocket is less than the pitch ofthe chain and therefore the chain would not fit the sprocket if wrappedthereabout. Further, no matter how much resistance is offered to thechain through said sprocket, the chain will always hug the sprocket, orin other words, the more resistance offered by the sprocket to the chainthe tighter will the chain cling to the sprocket.

Also it will be observed that this tangentially driven sprocketcomprises means to prevent an outward thrust on the chain sufficient toallow said chain to become. disengaged from the sprocket, said meanscompris ing the plurality of non-radial or hookshaped teeth 19 which areoutwardly and backwardly inclined with relation to the direction ofrotation of the sprocket, and a pocket 30 associated and coactingwiththe working face 16 of each tooth.

Lastly, it willbe seen that this sprocket has a pocket formed at thebase of the working face only of each tooth which is adapted to receiveand hold against radial displace- ,the outwardly and backwardlyinclination of of the chain into the pocket 30 associated with saidtooth as the preceding pintle leaves its pocket. i

It is obvious that those skilled in the art ,may vary the details ofconstruction as Well as the arrangements of .parts without de-' partingfrom the spirit of-the invention,

, therefore it is not desired to be limited to the foregoing disclosureexcept as may he demanded by the claims.

What is claimed is:

1. In a sprocket the combination of a plurality of teeth whose pitch isless than the pitch of the chain coacting therewith said teeth having a.working face outwardly and backwardly inclined; a pocket formed by eachtooth adapted to receive and hold a pintle of said chain;and meansadapted to direct said pintle into saidpocket.

2. In a sprocket the combination of a plurality of teeth whose pitch isless than the pitch of thechain coacting therewith; a. pocket formed byeach tooth adapted to receive and hold a pintle of said chain; and meansadapted to direct said pintle into said pocket as, the preceding pintleleaves its pocket.

3. In a sprocket the combination of a plurality ofteeth whose pitch isless than'the pitch ofthe chain coacting therewith; a

pocket formed by each tooth adapted to re-' ceive and hold a pintle ofsaid chain; and means disposed at the end of each tooth adapted todirect said pintle into said pocket,

a chain, means including a pluralityof hookshaped teeth to prevent anoutward thruston said chain disengaging the same from the sprocket whenthe chain isin tangential relation thereto, said teeth having a pitchless than the pitch of the chain coacting therewith as well as a flatworkingface for the pintles of said chain.

6. In a sprocketadapted to be driven by a chain, means including aplurality of nonradial teeth to prevent an outward thrust on said chaindisengaging the same from the sprocket when the chain is in tangentialrelation thereto, said teeth having a pitch less than the pitch of thechain coacting therewith as well as a flat working face for the pintlesof said chain.

7. In a sprocket adapted to be driven by a chain,.means including aplurality of outwardly andbackwardly incline-d teeth to prevent anoutward thrust on said chain disengaging the same from the sprocket whenthe chain is intangential relation thereto, said teeth having a pitchless than the pitch of the chain coactingv therewith as'ewe'll as a flatworking face for the pintles of said chain.-

8. In a sprocket adapted to be driven by a chain, means including apluralityof nonradial teeth and a'pocket associated with each when thechain is in tangential relation thereto, said teeth having a pitch lessthan the pitch of the chain coacting therewith as well as a fiat wor:ing'face for the pintles oi said chain.

9. In asprocket adapted to be driven by a chain, means including aplurality of nonradial teeth having a flat working face and a pocketcoa'cting with the working face 01 each to prevent an outward thrust onsaid chain disengaging the same fromithe sprocket when. the chain is intangential relation thereto, said teeth having ap'itchless than thepitch of the chain coacting therewith. 10. In a sprocket adapted to bedriven by chain, means comprising a'plurality of nonradial teeth eachprovided with a bevelled end, and pocket coacting with the working faceand said bevel end of each tooth to prevent an outward thrust'on saidchain disengaging; the same from the sprocket when the chain is intangential relation thereto.

11. The combination with a chain of a sprocket provided with means toincrease, the pressure therebetween upon increasing the drivingresistance of the sprocket when said chain is in tangential relationthereto, said means adapted to provide a positive and free engagementand disengagement. of said chain. i r

12. The combination with a chain of a sprocket having teeth whose pitchis less than the pitch of the chain, each tooth being provided withmeans to direct the pintles-of said chain into a pocket associated witheach tooth. Y

13. The combination with a chain of a sprocket having; teeth whnse pitchis less than the pitch of the chain, each toothbeing provided with meanscomprising a rearwardly bevelled end portion to direct the pintlespocket formed bythe working face of each tooth adapted to receive andhold a pintle of said chain; and nieansadapted to direct said pintleinto said pocket. i l

16. The combination with a chainof a sprocket having a plurality oiteeth whose pitch is less than the pitch of said chain; a pocket formedby theworking face of each tooth adapted to receive and hold againsteos-see and means associated'witli said pocket and" working face adaptedto direct said pintlo into said pocket. i, 1.

17. The combination with-"a chain ofa sprocket having a plurality ofnon-radial teethwhose pitchis less than the pitch-of said chain; apocket formed by each toothadapted to receive and hold a pint-1e ofsaidI chain; and means att-he end of each tooth adapted to direct saidpintle into said pocket.

iIn testimony whereofl aflixlmy signature.v TREADWAY B. MUN-ROE.

radial-displacement a pintle 'ofsaid chain; 1

int

